Yanmar 3YM27A 29HP Diesel Marine Inboard Engine
The Yanmar 3YM27A 29HP Diesel Marine Inboard Engine is a compact, mechanically controlled marine diesel engine designed for dependable propulsion in compatible small vessels and lifeboat installations.
Producing 29 metric horsepower (21.3 kW) at 3,200 RPM, the Yanmar 3YM27A combines a 1.115-litre, three-cylinder diesel engine with naturally aspirated operation, mechanical fuel control, and freshwater cooling through a seawater-cooled heat exchanger.
Its straightforward mechanical design makes it a practical choice for operators seeking reliable starting, manageable maintenance requirements, and consistent performance.
Unlike the recreational Yanmar 3YM30AE, the 3YM27A is specifically documented by Yanmar as a lifeboat-rated marine propulsion engine. Its suitability for a recreational sailing yacht or other vessel must therefore be confirmed against the intended application and relevant regulatory requirements.
At JB Marine GmbH, customers can enquire about the Yanmar 3YM27A, including available engine configurations, compatible marine gearboxes, installation accessories, warranty terms, and international delivery.
Why Choose the Yanmar 3YM27A?
29 HP Three-Cylinder Diesel Performance
The Yanmar 3YM27A develops a maximum rated output of 21.3 kW (29 PS) at 3,200 RPM.
Its inline three-cylinder configuration provides a compact source of marine propulsion power, particularly for installations requiring a mechanically controlled diesel engine.
The manufacturer also publishes a continuous rating of 19.4 kW (26.4 PS), which is important when assessing the engine for sustained operation.
Mechanical Engine Control
One of the principal advantages of the Yanmar 3YM27A marine diesel engine is its mechanical engine-control arrangement.
Unlike modern electronically controlled common-rail engines, the 3YM27A uses a conventional mechanical fuel-control system.
This offers several practical benefits:
- Straightforward engine operation
- Reduced dependence on complex electronic management
- Familiar mechanical maintenance procedures
- Practical servicing and inspection
- Suitability for specified marine safety applications
Regular fuel-system servicing and correct engine adjustment remain essential.
Naturally Aspirated Diesel Design
The Yanmar 3YM27A is a naturally aspirated diesel engine.
Because it does not rely on turbocharging to achieve its rated output, the engine has a relatively uncomplicated air-intake arrangement.
This can simplify routine inspection and eliminate turbocharger-specific maintenance requirements.
Freshwater Cooling with Heat Exchanger
The standard Yanmar 3YM27A uses freshwater cooling with a seawater-cooled heat exchanger.
Engine coolant circulates through the internal cooling passages, while seawater removes heat through the heat exchanger.
This helps maintain controlled engine temperatures and reduces direct seawater exposure inside the engine.
Yanmar also identifies a separate 3YM27AK keel-cooled configuration. The two cooling arrangements should not be confused when ordering replacement engines or components.
Compact Marine Installation
The 3YM27A has a compact installation footprint.
With the specified KM2P-1 marine gearbox, the published dimensions are approximately:
- Length: 715 mm
- Width: 534 mm
- Height: 649 mm
- Dry weight: 147 kg
These measurements are useful when assessing engine-room clearance, replacement suitability, and transport requirements.
Designed for Lifeboat Propulsion
Yanmar’s manufacturer documentation identifies the 3YM27A as a marine propulsion diesel engine for lifeboat applications.
This makes correct identification, installation, and regulatory compliance especially important.
For a lifeboat replacement project, verify that the exact engine configuration and associated equipment satisfy the vessel’s approval requirements.
For recreational or other commercial vessels, confirm application suitability with Yanmar before purchasing.
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | Yanmar |
| Engine model | 3YM27A |
| Engine type | Four-stroke, water-cooled diesel |
| Engine configuration | Inline three-cylinder |
| Displacement | 1.115 litres |
| Maximum rated power | 21.3 kW / 29 PS |
| Maximum rated speed | 3,200 RPM |
| Continuous rated power | 19.4 kW / 26.4 PS |
| Continuous rating speed | 3,101 RPM |
| Bore × stroke | 76 × 82 mm |
| Aspiration | Naturally aspirated |
| Combustion system | Swirl-chamber diesel combustion |
| Engine control | Mechanical |
| Cooling system | Freshwater cooling with seawater-cooled heat exchanger |
| Lubrication system | Pressure lubrication with trochoid pump |
| Starting system | Electric motor |
| Battery requirement | 12V, minimum 96 Ah (5-hour rate), 575A CCA as specified |
| Crankshaft rotation | Counterclockwise, viewed from stern |
| Propeller shaft rotation | Clockwise, viewed from stern |
| Compatible marine gearbox | Yanmar KM2P-1 |
| Forward reduction ratios | 2.21:1 or 2.62:1 |
| Reverse reduction ratio | 3.06:1 |
| Length with KM2P-1 | 715 mm |
| Width | 534 mm |
| Height | 649 mm |
| Dry weight with KM2P-1 | Approximately 147 kg |
| Documented primary application | Lifeboat marine propulsion |
Technical specifications are based on Yanmar’s published 3YM27A documentation. The 29 PS designation represents metric horsepower. Engine configuration, supplied accessories, and exact installation requirements should be confirmed against the manufacturer’s documentation and engine identification plate.
Compatible Gearboxes and Control Systems
Yanmar KM2P-1 Marine Gearbox
The manufacturer identifies the Yanmar KM2P-1 marine gearbox as the matching transmission for the 3YM27A.
This gearbox uses a constant-mesh gear arrangement with a servo-cone clutch.
Published transmission specifications include:
| Gearbox specification | Details |
|---|---|
| Gearbox model | Yanmar KM2P-1 |
| Gear type | Constant mesh |
| Clutch | Servo-cone |
| Forward reduction ratio — option 1 | 2.21:1 |
| Forward reduction ratio — option 2 | 2.62:1 |
| Reverse reduction ratio | 3.06:1 |
| Output rotation | Clockwise, viewed from stern |
| Approximate gearbox dry weight | 9.8 kg |
The appropriate reduction ratio depends on the vessel, propeller, shaft arrangement, and intended operating conditions.
The KM2P-1 gearbox must not be assumed included in every engine quotation.
Shaft-Drive Compatibility
The documented 3YM27A configuration is intended for conventional inboard marine propulsion using a suitable gearbox and propeller shaft.
Before installation, verify:
- Existing gearbox and reduction ratio
- Propeller shaft dimensions
- Shaft coupling
- Engine mounting points
- Propeller diameter and pitch
- Exhaust connections
- Cooling-water connections
- Engine-room clearance
Saildrive Compatibility
The manufacturer’s referenced 3YM27A specification identifies the KM2P-1 marine gearbox rather than a saildrive.
Saildrive compatibility should not be assumed.
If your vessel requires a saildrive installation, request confirmation from Yanmar regarding a suitable approved engine and drive combination.
Engine Controls and Instrumentation
The 3YM27A uses mechanical engine control.
Depending on the supplied configuration, the installation may require:
- Mechanical throttle control
- Gear-shift control
- Electric starting controls
- Engine warning indicators
- Instrument panel
- Wiring harness
- Appropriate battery and charging connections
The exact equipment supplied must be confirmed in the quotation.
Engine Duty Rating and Applications
Yanmar publishes two important power ratings for the 3YM27A:
Maximum output: 21.3 kW (29 PS) at 3,200 RPM.
Continuous output: 19.4 kW (26.4 PS) at 3,101 RPM.
These figures should not be treated as interchangeable.
The maximum rating describes the engine’s published maximum output, while the continuous rating is relevant when assessing sustained operating requirements.
Suitable Applications
The manufacturer’s documented application is:
- Lifeboat marine propulsion
Other potential installations require confirmation of technical suitability and regulatory compliance.
The 3YM27A should not automatically be treated as interchangeable with the recreational Yanmar 3YM30AE simply because both have approximately 29 HP ratings.
Price, Package Contents and Warranty
Yanmar 3YM27A Engine Price
Price: Contact JB Marine GmbH for a quotation.
The final price depends on the engine’s condition, configuration, gearbox requirements, supplied accessories, and delivery destination.
Customers can enquire about:
- Yanmar 3YM27A engine assembly
- 3YM27A with KM2P-1 gearbox
- Replacement engine for a compatible existing installation
- Required controls and installation accessories
Availability must be confirmed before ordering.
What’s Included in the Engine Package?
The exact supplied package depends on the specific engine offered.
An engine assembly may include:
- Three-cylinder diesel engine
- Mechanical fuel injection equipment
- Cooling-system components
- Electric starting equipment
- Standard engine accessories
Before purchasing, confirm whether the quotation includes:
- KM2P-1 marine gearbox
- Engine mounts
- Instrument panel
- Wiring harness
- Throttle and shift controls
- Exhaust mixing elbow
- Fuel-system accessories
- Propeller shaft coupling
- Installation documentation
Only components expressly identified in the quotation should be considered included.
Warranty Information
Warranty coverage depends on the engine’s condition, manufacturing year, supply channel, and applicable manufacturer or seller terms.
Eligible new engines may qualify for manufacturer warranty coverage subject to the relevant conditions.
Used, reconditioned, or older-stock engines may have different warranty arrangements.
JB Marine GmbH will confirm the applicable warranty terms before purchase.
Frequently Asked Questions
How Much Horsepower Does the Yanmar 3YM27A Produce?
The Yanmar 3YM27A produces a maximum of 29 PS (21.3 kW) at 3,200 RPM.
Its published continuous output is 26.4 PS (19.4 kW).
What Is the Displacement of the Yanmar 3YM27A?
The engine has a displacement of 1.115 litres and uses an inline three-cylinder configuration.
Is the Yanmar 3YM27A Turbocharged?
No. It is a naturally aspirated diesel engine.
What Gearbox Is Compatible with the Yanmar 3YM27A?
Yanmar identifies the KM2P-1 marine gearbox, with published forward reduction ratios of 2.21:1 and 2.62:1.
Is the Yanmar 3YM27A Freshwater Cooled?
Yes. The standard 3YM27A uses freshwater cooling with a seawater-cooled heat exchanger.
A separate 3YM27AK configuration uses keel cooling.
What Is the Weight of the Yanmar 3YM27A?
The published dry weight is approximately 147 kg with the KM2P-1 gearbox.
Does the Yanmar 3YM27A Use Electronic Fuel Injection?
No. The engine uses mechanical fuel control and a conventional diesel injection arrangement.
Is the Yanmar 3YM27A Suitable for a Sailing Yacht?
Suitability must be confirmed. Yanmar documents the 3YM27A as a lifeboat propulsion engine, whereas the 3YM30AE is part of its recreational marine engine range.
Is the Yanmar 3YM27A the Same as the 3YM30AE?
No. Although both are associated with approximately 29 metric horsepower, they have different published displacements and intended applications.
The 3YM27A has a displacement of 1.115 litres, while the 3YM30AE has a displacement of 1.266 litres.
Can I Order the Yanmar 3YM27A with a Gearbox?
A quotation can be requested for an engine and compatible gearbox package, subject to availability and confirmation of supplied equipment.
Buy the Yanmar 3YM27A 29HP Marine Diesel Engine from JB Marine GmbH
Looking for a Yanmar 3YM27A 29HP diesel marine inboard engine for sale?
At JB Marine GmbH, customers can enquire about the Yanmar 3YM27A for compatible marine propulsion and replacement projects.
Whether you’re replacing an existing lifeboat engine or sourcing a compatible marine diesel installation, selecting the correct engine and transmission configuration is essential.
For an accurate quotation, please provide:
- Existing engine model and serial number
- Vessel type and intended application
- Required quantity
- Gearbox requirements
- Preferred reduction ratio
- Required controls and accessories
- Delivery country and destination
Contact JB Marine GmbH today for Yanmar 3YM27A pricing, availability, package details, warranty information, and international shipping quotations.
Website: https://jbmarinegmbh.de/
